鉄筋コンクリート外部柱・梁接合部のせん断抵抗機構

抄録

An analytical method was proposed to evaluate the shear capacity of exterior R. C beam-column joints. In the analysis, three types of shear resisting mecanisms were introduced: a concrete compression strut mechanism, a regular truss mechanism and a composite mechanism of concrete compression strut and fan-shaped truss action. Considering the transition of bond stress distribution along column bars and the effectiveness of shear reinforcement, the rational analytical procedure was developed based on equilibrium equations derived from these mechanical models. This analytical method was applied to previously reported test specimens, and the experimental results concerning the effect of column axial force, horizontal shear reinforcement and intermediate column bars on the shear capacity of the joints were satisfactorily explained. The following important characteristics were presented qualitatively by the analysis. 1) The larger the column axial load is, the smaller amount of horizontal shear reinforcement is required. 2) The role of intermediate column bars is not to construct the truss mechanism but to make the concrete compression strut wider. 3) When beam bars are anchored in the joint with standard hooks, more than two thirds of the total tensile force is developed in the bent portion.